Process of vulcanizing rubber and products obtained thereby



Patente cl Oct. 4, 1932 a 1110 Drawing.

oswem) BEHRENQQF-iTITfiO, wns'r vraernrn, Jessie-non T THERUBBER snavron00., 0F AKRON, OHIOfA' CQRPORATION OF OHIO feRooEss or vutonnrzrneBunsen, min rnonuo'rs OBT INED THEREBY The present invention relatesdtothe'vul- I canization of rubber by an improved process whereby avulcanized product of high. quality is produced- More particularly thepresent invention relates to the vulcanization of rubber wherein thepreferredclass of compounds, for example a i-product obtained byreacting a chlorinated aldehyde amine reaction "product with amercaptobenzo-thiazole or a salt thereof, s employed as avulcanizationaccelerator. 1

, One of the preferred class of materials was prepared in the followingmanner. Substantially one molar portion each of butyl aldehydeandaniline were reacted at a temperature preferably below 40 C. T0 thebutyl aldehyde-aniline I condensation 7 product thus formed,substantially two molar portions (144; parts) of butyl aldehyde werestirred in as rapidly as possible, the reaction vessel was then closedtightly and agitation stopped and thereaction allowed to proceed underits own heat of reaction, preferably at.1 10 120120 Cgand a pressure ofapproximately five to ten pounds per square inch. Afterthe initialreaction had'subsided the reaction mass was heated for substantially 40hours at approximately .90 to, 95 C.-

v If convenient or desirable, a catalyst or condensing agent, forexample an organic acid, may be added, with the secondquantity of Vbutyl aldehyde. On completionof'the reae tionas described, the wateroflcondensation was separated from the product thus formed. 7, Any sidereaction products that may be present were removed preferably by steamdistillation and chlorine passed into the residual product dissolvedinan organic solvent, for example benzene, until saturawas-completed. 7

takes place at approximately 15 to25 C.

tion of the aldehyde-amine reaction product This reaction preferably Thechlorinated aldehyde-amine reaction product, after separation fromthesolvent employed, preferably by evaporation of the solvent therefrom,was reacted preferably in an alcoholic medium with an equivalent amountof thesodium salt of mercapto-benzo-thiazole preferably at approximately50 to 60 C. An oil was thus formed, which,

Application filed December 18, 1929. Serial No, 415,129.

after washing first with an alkali, for example an aqueous sodiumcarbonatesolution, lthen'with Water, and finally drying, wasincorporated in a rubber stock comprising 100 parts of pale crepe rubber5v "parts of Zinc oxide 3.5 parts of sulfur 1 0.5-part of acceleratorThe rubber stock thus formed was then cured by heating in a press fordifferent periods of timeand atthe temperature given by 40 pounds ofsteam pressure per s'quare inch,'- that is 287 F. The cured stock ontesting was found to have the following tensile characteristics:

' Table I Modulus of elasticity in a lbs/in v at elongations ia gif Timeof cure break elongain tion 390% 500% l 700% lbs/1n per cent 15 mins. at287 F 366 933 3345 3635 710 30 IIllZlS. at 287 F 297 970 3575 3905 720mins. at 287 F 294 1037 3810 4200 720 The data set forth invTable I showthat the accelerator incorporated in thestock described, constitutes amember of an exceptionally efficient class of rubbervulcanizationaccelerators.

Another mode of operating the present invention comprises the following:i The reaction product of substantially three molecular proportions ofacetaldehyde and substantially two molecular proportions of aniline,prepared as described in U. S. Patent 1,659,152 granted to Clayton OlinNorth February 14:, 1928, was dissolved in an organic-solvent, for"example carbon tetrachloride and chlorine Was passed thereinto atsubstantially 40 to 0. until saturation of the aldehyde-amine reactionproduct was complete. After separation of the carbon tetrachloride fromthe reaction product, preferably by evaporation or distillation, asolvent, preferably alcohol was added to the residual productand thechlorinated aldehyde amine product further reacted with an equivalentamount of an alkali metallic salt of mercapto-benzo-thiazole, preferablythe sodium salt of mercapto-benzosthiazole. The product thus formed, onseparation from the solvent medium preferably by evaporation or flOdistillation of the solvent therefrom,; was

' washed first with aweak alkaline solution, for example anajopu'eoussodium carbonate so lutionand then with'water to eliminate any unreactedmercapto-benzo thiazole.,

' 'A' portion of the material prepared as de-" scribed was incorporatedin the well known manner arubberstock comprising 7 'after curingbyheating in a. press for dilfer- V i 3.5 parts of sulfur 100 parts ofpale'crepe rubber parts of zinc'oxide '.8' parts of accelerator Samplesof the compounded rubber stock,

' ent periods of time at the temperature given by 40 pounds 'ofisteampressure per square inch that is 287 F., on testing were found topossess the following tensile characteristics Another of the preferredclass of rubber vulcanization accelerators comprises the product formedby reacting a mercapto-benzo-thiazole with a. chlorine derivative of aheptaldehyde-aniline condensation product.

Thus to the product formed by. combining substantially two molecular"proportions of heptaldehyde with substantially one molecularproportionof aniline, chlorine was passed I so therein at a temperatureof approximately 30 to until saturation of the aldehydeamine product wasreached. The product thus formed was then reacted, preferably in analcoholic solution, with" an equivalentquantity'of analkali metallicsalt of mercapto-benzo-thiazole, for example the sodium salt ,ofmercapto-benzo-thiazole, by heatingto approximately 50 to C. Oncompletion of the reaction, the sodium" chloride formed was filtered offand the desired product separated from the filterate, preferably by theevaporation or distillation of the sol- -"vent therefrom. The residue,after washing first with an alkaline solution, preferably with anaqueoussodium carbonate solution, to eliminate any 'unreactedmercapto-benzothia zole and then with water, was driedand thenincorporated in arubber mix comprising 1100 parts of pale crepe rubber 5parts of .zinc oxide t 3.57 parts of sulfur;

I .37 5 "parts of accelerator" in a short time and The rubber stock thusformed after curing by heating in a pressin the well known manner fordifferentperiods of time at thetemperature given by 40 pounds of steampressure per square inch, that is 287. F., on testing Was'found topossess the following tensile characteristics: 7

Table III -Mp'd1z1us oflgelasg lQlyYlD sin z T atelongation Tensile at31 53 fl ime of-cure I brealgigl vmm l percent 1 0mins.'at287 F l l '3381140 3075 I 650 20'rnins.-at 287-F 385 v .1443. 4240 680 Fromtheexamples setforth it is seen that the preferred class of materialsexhibitdesirableacceleratingcharacteristics, causing aIllbbBI'rCOIIlPOSltlOII of vulcanization characteristics in which theyare incorporated, prior to'thevulcanization thereof, to be curedproducing a rubber possessing high-quality. I

Other aldehyde-amine products than those hereinbefore set forth. may behalogenated and reacted with a mercapto-benzothiazole and formfurtherexamples of the preferred class of rubbervulcanizationaccelerators.

Thus anhydro formaldehydeeaniline, methylene dianilide,acrolein-aniline, heptaldehyde Y dianilide, butyl aldehydeaniline, butylaldehyde dianilide and analogous aldehydeamine reaction products maybehalogenate ed and further reactedw'ith a mercapto- Ibenzo-thiazole,for examplethe sodiumsalt of mercapto-benzo-thiazole" andemployed in a rubber composition of vulcanization characteristics in amanner similar-to that hereinbefore set forth. 1 i

The presentinvention is limited solely by I the claims comprising a'part of the present specification, wherein it is intended to claim theinvention as broadly as possible in view of the "prior art. i What isclaimed is: p

1. A process of vulcanizing 'rubber'comprising heating rubber and sulfurin the presence of a vulcanizationaccelerator comprising a reactionproduct of a mercaptobenzothiazoleand a. chlorinatedaldehyde-- i amineproduct, said. amine comprising an aromatic hydrocarbon wherein one ormore ydrogen atoms *are substituted by, amino groups only. i V i I ,1 2.A process of vulcanizing rubber comprising cheating rubber and sulfur inthe presence of a' vulcanization accelerator comprising a reactionproduct of a mercaptobenzothiazole. and a; chlorinated aliphaticaldehyde-primary aromatic amine reaction product containing a singlebenzene nucleus. 7

. 3. A process of .vulcanizing,rubbercomprising heating rubber andsulfur in the presence of a vulcanization accelerator comprising areaction product of a mercaptobenzothiazole and a chlorine derivative ofan aliphatic aldehyde-aniline reaction prod- 1 uct.

4. A process of vulcanizing rubber com prising heating rubber and sulfurin the pres ence of a vulcanization acceleratorv comprising a reactionproduct of a mercapto benzothiazole and a chlorine derivative of acondensation product of an aliphatic aldehyde containingless than eightcarbon atoms and aniline.

5.A process "of vulcanizing rubber comprising .heating rubber and sulfurin the presence of a vulcanization acceleratorcomprising a reactionproduct of a mercaptobenzothiazole and a chlorine derivative of areaction product of substantially three molecular proportions of analiphatic aldehyde containing less than eight carbon atoms andsubstantially one molecular proportion of aniline.

6. A process of vulcanizing rubber comprising heating rubber and sulfurin the presence of a vulcanization accelerator comrisin a reactionrcduct of a merca to benzothiazole and a chlorine derivative of areaction product of substantially three molecular proportions of butylaldehyde and substantially one molecular proportion of aniline.

7. A process of vulcanizing rubber comprising heating rubber and sulfurin the presence of a vulcanization accelerator comprising a reactionproduct of t he sodium salt of mercaptobenzothiazole and a chlorinederivative of a reaction product of substantially three molecularproportions of butyl aldehyde and substantially one molecular proportionof aniline.

8. A vulcanized rubber product prepared by heating rubber and sulfur inthe presence of a vulcanization accelerator comprising a reactionproduct of a mercaptobenzothiazole and a chlorinated aldehyde-amineproduct, said amine comprising an aromatic hydrocarbon wherein one ormore hydrogen atoms are substituted by amine roups only.

9, A vulcanized rubber product prepared by heating rubber and. sulfur inthe presence of a vulcanization accelerator comprising a reactionproduct of a mercaptobenzothiazole and a chlorinated aliphatic aldehyde-primary aromatic amine reaction prodnot containing a single benzenenucleus.

.10. A vulcanized rubber product prepared by heating rubber and sulfurin the presence of a vulcanization accelerator comprising a reactionproduct of a mercaptobenzothiazole and a chlorine derivative of analiphatic aldehyde-aniline reaction product.

11. A vulcanized rubber product prepared by heating rubber and sulfur inthe presence of a vulcanization accelerator comprising a reactionproduct of a mercaptobenzothiazole and a chlorine derivative of areaction product of an aliphetic aldehyde containing less than eightcarbon atoms and aniline.

12. A vulcanized rubber product prepared by heating rubber and sulfur inthe presence of a vulcanization accelerator comprising areaction'product of a mercaptobenzothiazole and a chlorine derivative ofa reaction product of substantially three molecular proportions of analiphatic aldehyde containing less than eight carbon atoms andsubstantially one molecular proportion of aniline.

13. A vulcanized rubber product prepared by heating rubber and sulfur inthe presence of a vulcanization accelerator comprising a reactionproduct of a mercaptobenzothiazole and a chlorine derivative of areaction product of substantially three molecular proportions of butylaldehyde and substantially one molecular proportion of aniline.

14-. A vulcanized rubber product prepared by heating rubber and sulfurin the presence of a vulcanization accelerator comprising a reactionproduct of the sodium salt of mercaptobenzothiazole and a chlorinederivative of a reaction product of substantially three molecularproportions of butyl aldehyde and substantially one molecular proportionof aniline.

15. A process of vulcanizing rubber comprising heating rubber and sulfurin the presence of a vulcanization accelerator comprising a productprepared by reacting substantially equimolecular proportions of thesodium salt of mercaptobenzothiazole and a chlorine derivative of areaction product of substantially three molecular proportions of butylaldehyde and substantially one molecular proportion of aniline.

16. A vulcanized rubber product prepared by heating rubber and sulfur inthe presence of a vulcanization accelerator comprising a productprepared by reacting substantially equimolecular proportions of thesodium salt of mercaptobenzothiazole and a chlorine derivative of areaction product of substantially three molecular proportions of butylaldehyde and substantially one molecular proportion of aniline.

In testimony whereof I hereunto affix my signature.

OSWALD BEHREND.

